Strategies for Controlling Particle Size in Injectable Nanosuspensions and Emulsions: Techniques and Future Opportunities

Particle size is crucial for injectable nanosuspensions and emulsions, significantly impacting their performance. Achieving optimal particle size is essential in parenteral formulations, and various methods and equipment are available for this purpose. For nanosuspensions, standard manufacturing techniques include ionic cross-linking, solvent evaporation, hot homogenization, SEA-PES, and wet milling with crystalline APIs. Nanoemulsions, on the other hand, are typically produced using homogenization and solvent evaporation. This review focuses on achieving particle sizes below 200 nm using bead milling, spray drying, microfluidics, and high-shear homogenization techniques. In addition, sterilization of these nanoformulations can be accomplished through filtration using a 0.22 μm redundant filter and focuses on forthcoming tips on conventional methods and emerging opportunities for improving nanoformulation processes.